The objective of this study is to assess the potential mechanism by which Troglitazone improves skeletal muscle insulin sensitivity in patients with Non-Insulin Dependent Diabetes Mellitus (NIDDM) and compare these to the effects of Metformin and sulfonylurea treatments. The hypothesis to be tested is that troglitazone has a greater effect to improve skeletal muscle insulin sensitivity than does metformin or sulfonylurea therapy.